论文部分内容阅读
笔者采用等离子质谱仪(ICP-MS)方法对北秦岭大荆区奥陶纪—志留纪庙湾组黑色岩系岩石的稀土元素及V、Ni、Cr、U、Th等微量元素含量进行了测定。结果显示岩石轻稀土元素相对重稀土元素富集,Eu异常值δEu为0.63～10.61(绝多数大于1.54)多呈正异常,Ce异常值δCe为0.65～1.02(平均为0.893)异常微弱且有正负差异;U/Th值为0.38～4.07,w(V)/w(V+Ni)值为0.38～0.93以及w(Ce)/w(La)值为1.27～2.17。将这些特征值与前人研究成果对比,并利用La/Yb-Ce/La和La/Yb-REE判别图解判别后,认为北秦岭区庙湾组黑色岩系形成于活动陆缘一种干燥缺氧较深浅海环境,黑色岩系形成过程中有热液作用参与。
The authors used ICP-MS method to analyze the REE, V, Ni, Cr, U, Th and other trace element contents in the black rock series of the Ordovician-Silurian Miaowan Formation in Dajing District, North Qinling. Determination. The results show that the light rare earth elements are enriched in heavy rare earth elements. The Eu anomalies δEu range from 0.63 to 10.61 (most of them are larger than 1.54), while the anomaly values of δ Ce range from 0.65 to 1.02 (average 0.893) (U / Th) was 0.38 ~ 4.07, w (V) / w (V + Ni) was 0.38 ~ 0.93 and w (Ce) / w was 1.27 ~ 2.17. Comparing these eigenvalues with those of previous studies, and using the La / Yb-Ce / La and La / Yb-REE discrimination diagrams, it is concluded that the Miaowan Formation black shale in North Qinling is formed in a dry land margin Oxygen is deeper and shallow sea environment, hydrothermal interaction is involved in the formation of black rock series.